Lesson video

Welcome to today's lesson on atoms and elements.

It's part of the Unit: Atoms, elements, and compounds.

I'm really pleased that you've come along to learn with me today.

My name's Mrs. Mytum-Smithson.

Although this topic may seem a little bit tricky, I know that by the end of this lesson, you are going to be able to describe what a chemical element is and give some examples.

Some of the words you may be familiar with and others may be new, but if you work through this bit by bit, by the end of the lesson, you should be confident about elements.

Here are some of the keywords, matter, atom, element.

On the next slide, there's some definitions that go along with these, so feel free to pause and read along if you wish to do so.

Everything is made up of matter.

This is quite a large statement, but it's quite simple, if it takes up volume, so if it takes up some space and it's got a mass, then it's matter, that's as simple as it is.

Everything exists in one of three states of matter, so here they are, the solid state, the liquid state, and the gas state.

Those purple circles there represent particles and it's those particles that make up matter.

To see if something's got matter or not, we can look and see if it takes up some volume, so if it takes up some space, and it's got a mass associated with it.

So let's have a look at our first example.

Here's something in the solid state.

It's a plastic toy duck and it's got a mass of 35 grammes.

So we know that that toy duck is made of matter.

Here's orange juice, it's in the liquid state, and this glass of orange juice has got a mass of 280 grammes.

Again, it's fairly straightforward to see, that you can see it's got volume and you can see it's got mass associated with it, so it's made of matter.

What can be a little bit tricky is thinking about the gas state and these helium balloons.

So what about these balloons filled with gas? Does helium have mass? Is it made of matter? Does it take up volume? We're going to carry out a little bit of an experiment now, and this is going to help us understand if gas has got matter or not.

So the matter of the deflated balloon is recorded, so that's a balloon before it's been blown up.

And here is the inflated balloon, so this balloon has been blown up, and it's the same balloon as we took the mass off before.

So we're going to take the mass of it again, now it's inflated.

What I would like you to do is just have a little think and predict the mass of the inflated balloon.

All I want you to think about is, will it be higher, lower, or the same mass as the deflated balloon? So just have a little think now, I'm gonna pause the video for you.

Here's our experiment now in real life.

So here's the deflated balloon.

We can see from the balance that it's got a mass of 1.

5 grammes.

So have a little look.

Now what we're going to do is I'm gonna show you a little clip and this little clip is showing you the balloon on the balance again, but this time, it's inflated.

So remember you're thinking, "Is it higher, is it lower, or is it the same mass as the deflated balloon?" So here we go, we're gonna blow this balloon up now, we're gonna place it on the balance, and you can read that scale there, and you should read it, it says 1.

8 grammes.

You can have a look at this video again if you want.

It says 1.

8 grammes, and there it is, I've got a still picture for you.

So, when the balloon was inflated with air, the balloon increases by a mass of 0.

3 grammes.

Were you correct or were you not correct? That means that the air that has been inflating the balloon has got mass, therefore, it's made up of matter.

So well done if you said the correct prediction, I've got a quick check for understanding.

If something has mass, it shows that it is made of matter.

Is that statement true or is that statement false? Pause the video for some thinking time, and press play when you've got an answer.

So if something has mass, it shows that it's made of matter that is indeed true.

So I want you to justify your answer.

So you've got, all things have mass except for gases, they only take up volume.

And if something has mass and takes up volume, it is made of matter.

Pause the video for thinking time, and press play when you're ready for the answer.

Well done if you said B, if something has got mass and takes up volume, it's made of matter.

Just like we saw in the balloon experiment, that balloon had a greater mass when it was filled with air, showing that the air had mass.

Now we're going to have a bit more of a think about what matter is made up of.

Matter is made up of atoms. Now, if you imagine you could take a gold block and you would divide that gold block multiple times, eventually, you would end up with a single gold atom.

And that atom is the smallest building block of matter.

So let's have a look.

Here's our gold bar.

And you would cut it, and cut it, and cut it some more, and if you kept on cutting it in half each time, eventually, although you wouldn't be able to see it 'cause it would be too small, eventually you would end up with a single gold atom.

Now the word atom comes from Atomos and that comes from a Greek word meaning it "cannot be divided." You cannot divide an atom, and it'd still be an atom.

An atom is too small to be seen without a specialist microscope.

So the microscopes in your classroom would not be able to magnify an atom, a single atom, large enough to allow you to see it.

Now let's have a think about sand.

So we've got a single grain of sand, and that measures approximately 0.

1 millimetre.

How many atoms do you think is in that single grain of sand? I think you're going to be surprised because in a single grain of sand, there are approximately 30 quadrillion atoms. Now that's a 30 with 15 zeros after it, and that's the number of atoms in a single grain of sand.

Now to give you another example, an onion skin cell measures approximately 0.

1 millimetre.

In a single onion skin cell, there are approximately a hundred trillion atoms. That is 100 with nine zeros after it, and that is the number of atoms in a single cell.

Now this image had to be magnified underneath a microscope for us to see it.

So you can imagine the number of atoms that's in a whole onion, absolutely loads.

What is matter made of? Is it made of stuff? Is it made of atoms? Or, is it made of sand? Pause the video for some thinking time, press play when you want the answer.

Well done if you said that matter is made of atoms, well done.

Now we've got a quick true or false, atoms are small, but you can still see them using a microscope at school.

Is that true or is that false? Now I want you to justify your answer.

Atoms are very small, there are about 10 atoms in a grain of sand.

Microscopes at school are not powerful enough to see an atom because the atoms are too small.

What do you think, A or B? Pause the video now for some thinking time, press play when you've got your answer.

Well done if you said that microscopes at school are not powerful enough to see an atom 'cause the atoms are too small.

If you remember, we said that the atoms were so, so small, you would need a special microscope in order to see them.

Scientist John Dalton suggested a model of an atom.

Here's a picture of John Dalton looking very serious.

And he said that, "An atom is like a sphere that cannot be broken up." So this is how John Dalton imagined an atom to be.

He imagined it to be spherical like a ball, and you can't break that up.

So check for understanding, which image represents the way John Dalton imagined an atom to look like, was it A, is it B, or was it C? Pause the video for some thinking time, and press play when you've got your answer.

Well done if you said B, it's a sphere.

John Dalton imagined an atom to be like a sphere.

Now I've got a task to check your understanding of matter.

So I'd like you to correct the students' errors about matter and atoms. So Sam says, "Some things are made up of matter." Jacob said, "John Dalton suggested that atoms were like very small spheres that could or could not be divided." Lucas said, "Something is made from atoms." So there's a blank space for you to write your answer.

And Izzy is saying, "An atom is so big it cannot be seen with a human eye." So pause the video, complete the task, and then press play when you want the answers.

Well done for completing the task.

Let's go through the answers now.

Sam says, "Everything is made up of matter." "John Dalton suggested that atoms were like very small spheres that could not be divided." Lucas said, "Matter is made from atoms." And Izzy said that, "An atom is so small it cannot be seen with the human eye." Well done if you got all those right.

Now we're onto our second learning cycle of elements.

An element is a substance that's made up of only one type of atom.

So far, there's been 118 different elements that have been discovered, and we'll find these on the periodic table, and this contains a list of all known elements.

Here's a version of the periodic table.

You can see that there are 118 different elements written on there.

The Scientist, John Dalton, thought that each atom of an element was the same.

So he thought that all oxygen atoms were all the same type of sphere, but each element had got a different type of atom.

For example, a carbon atom would be different to an oxygen atom, but all carbon atoms would be the same type of sphere.

And again, with hydrogen, hydrogen atoms would all be the same as each other, but they would be different, to say, a carbon atom or an oxygen atom.

Now I've got to task for you.

I would like you to help Aisha complete her sentences.

The other students have given her some suggestions about what she should complete her sentence starter with.

So the first sentence is, "An element is.

." And Laura has suggested, "Made up of only one type of atom, made of more than one type of atom, or made of just one atom." And her second sentence is, "The total number of elements is.

." And Alex has suggested three numbers, "37, 100, or 118." And "The list of all known elements.

." Andeep is suggesting, "is found on the chemical table, is found on the periodic table, or is found on the element table." What I'd like you to do now is pause the video, complete the task, press play when you're ready for the answer.

So Aisha is now gonna tell Laura, Alex, and Andeep, which sentence she thinks that she should have chosen.

So, "An element is made up of only one type of atom." "The total number of elements is 118." And, "The list of all known elements is found on the periodic table." Well done for completing that task, and well done if you got those all right.

Now we're onto our third learning cycle of representing elements.

So some of the names of elements are from different places, so some are from Greek or Latin words.

For example, helium is from the Greek God of the Sun, Helios, and lead is from the Latin word "Plumbum." It's given the symbol Pb, and you'll know that that is also where the origin of the word plumber comes from.

Some of the elements are named after the country where they're from.

For example, Francium is named after France, the home country of the researchers who discovered it.

Some of them, are named after scientists.

Curium is named after Marie and Pierre Curie.

They were the pioneers of radioactivity.

So the origins of the names of the elements are really quite interesting, and perhaps if you got a little extra time, you could research them.

Each element is represented by one or two letters called a chemical symbol.

The first letter of any element symbol is always a capital letter, and the second one is always lowercase.

So for example, here's the first letter.

So carbon is represented just by a C, sulphur is just represented by an S, and that's a capital C and a capital S.

Now we've got gold and lead, they're represented by two letters.

So you've got A followed by u, and that is a capital A and a lowercase u for gold, and a capital P and a lowercase b for lead.

Now a quick check for understanding.

What's the correct way to represent the element helium? Is it capital H followed by capital E? Is it capital H followed by lowercase e? Is it lowercase h followed by lowercase e? Pause the video for some thinking time.

Press play when you want the answer.

Well done if you said capital H followed by a lowercase e.

That's right, there are always a capital followed by a lowercase.

So which is the correct way to represent an element? Is it A capital N, a lowercase b, an uppercase F, and an uppercase E? So which one of these is the correct way to represent an element? Pause the video for some thinking time, press play when you've got the answer.

Well done.

If you said N, capital N represents the element nitrogen.

The elements in different languages have got names.

So you can see here's some element names in Japanese, using the Japanese alphabet.

Here's some element names in French, so these are the French words for these specific elements.

Now, if we use the symbols to represent an element, it allows all the chemists across the world to communicate, I.

e.

, speak, using the same language.

It also makes it a lot quicker to write one letter or two letters rather than a whole word.

So this is another benefit of using one or two letters to represent an element.

Here's a check for understanding.

Select two correct answers about the way scientists represent elements with symbols.

So it is easier to write the element you are talking about.

The element symbols are the same no matter what language you speak.

Elements are not represented by symbols at all.

Different symbols are used in different countries to represent different elements.

What I'd like you to do now is pause video, and then press play when you've got your answer well done if you said A, it's easy to write the element you're talking about, much quicker to write one or two letters than a full word.

And also, the element symbols are the same no matter what language you speak.

So all scientists can communicate with each other no matter what country they're from.

Here's Task C.

Jun has to do his homework about elements.

He has a periodic table to use and he needs your help.

He has three parts of the task.

So the first part is to write symbols that represent carbon, lithium, helium, and manganese.

The second part is to write the names of these elements, so H, Co, Cu, N.

And then the third part of the task is to explain why it's useful for scientists to use symbols to represent elements.

Here's a periodic table for you to use if you've not got a printed one in front of you.

What I'd like you to do now is pause the video, then press play when you've got an answer.

Well done for completing that task, here's the feedback.

So the elements are represented, so carbon is represented by a capital C.

Lithium is represented by a capital L, followed by a lowercase i, helium, capital H, lowercase e.

Manganese, uppercase M, lowercase n.

Make sure that they are all starting with capitals and if they've got a second letter, it needs to be lowercase.

And number 2, you should have found that the elements were hydrogen, cobalt, copper, and nitrogen.

And the third part of the task was, it's useful for scientists to use symbols to represent elements so that they can speak or communicate with other scientists who might not speak the same language as them.

And also, it's quicker or easier to write a symbol, which is just two letters compared to the full name of the element.

So well done if you've got all that right, you've done really well! Now for the summary, to sum up everything that we've learned this lesson.

All matter is made up of atoms. Dalton's model of an atom is of a sphere that cannot be broken up.

Each element is made up of only one type of atom.

The periodic table contains a list of all known elements.

Each element is represented by chemical symbols, of which the first letter is always a capital, and the second one is lowercase, e.

g.

, Mg from magnesium.

Well done for working hard throughout this lesson, I think you've learned a lot about elements, I and hope to see you again sometime.